Flavonoids in Fruits and Vegetables May Cut Risk
A recent study shows that flavonoids, biological compounds found in more than 4,000 fruits and vegetables, seem to inhibit the growth of human cancer cells in laboratory tests.
The preliminary findings were presented at a recent meeting of the American Chemical Society in San Francisco.
The study, conducted in collaboration with the Department of Agriculture, focused on the 22 flavonoids found naturally in orange and tangerine juice.
Dr. Najla Guthrie, in presenting the findings, said the results are "very encouraging" and that these compounds could be effective against lung cancer, prostate cancer and melanoma cells.
The study also found that synthetically produced flavonoids effectively inhibited the growth of colon cancer cells.
Previous research conducted by Guthrie indicated that components found in citrus juices were shown to reduce the growth of human breast cancer cells in laboratory tests.
Dr. David Ringer of the American Cancer Society said the findings "further reinforce that flavonoids are an important class of chemo-protective compounds which are beneficial in lowering the risk for certain cancers and cardiovascular disease."
Both Ringer and Guthrie said more research is needed, especially to determine how these compounds metabolize in the body.
The American Cancer Society recommends a diet of five servings of fruits and vegetables daily. Dr. Ringer says there's enough epidemiological proof to show that a healthy diet can lower the risks for cancer.
Soy, Not Isoflavones, Fights Breast Cancer
Soy consumption has been shown to inhibit breast cancer, but isoflavones-a soy component assumed to provide those anti-cancer benefits-may not be that important, a new study has concluded.
The study casts doubt on the benefits of using purified soy isoflavones to cut the risk of breast cancer.
Researchers at the University of Illinois at Chicago (UIC) tested purified isoflavones against soy protein mixes with and without isoflavones in female rats to determine their effectiveness in reducing the incidence and the number of mammary gland tumors.
"There are well-established studies showing that soy is effective in helping prevent tumors. The assumption was that isoflavones would be the active ingredient, but we found a lot of surprises," Dr. Andreas Constantinou, a surgical oncologist at UIC's College of Medicine, said at an American Association of Cancer Research meeting.
Although all the compounds studied reduced the incidence of tumors, the soy protein mix without isoflavones was the most effective in decreasing the number of tumors, he said.
Constantinou suggested that the anti-tumor ingredient in the soy mixture works by increasing the production of two detoxification enzymes that shield cells from harmful substances called free radicals.
Other components of soy that could be responsible are dietary fiber, phytic acid or lignans, the researcher said.
Purified isoflavones have become commercially available as women at risk for breast cancer seek preventive measures against the disease.
Studies have shown an inverse relationship between the consumption of soybean products and breast cancer risk in premenopausal women.
In addition, the incidence of the disease is lower in Japan and regions of China-where a large percentage of daily caloric intake is from soybeans-than in Western industrialized countries where little or no soy is included in the diet.
"Based on these findings, I recommend against using purified soy isoflavones," Constantinou said.
Doubts Cast on Benefits of Shark Cartilage
Actually, sharks do get cancer. That discovery challenges a small industry based on the belief that shark cartilage contains some beneficial cancer-fighting substances.
Dozens of brands of shark cartilage supplements are sold in drugstores, promoted as treatments for cancer, arthritis and aging. The stuff is even put in dog biscuits.
One of the chief arguments behind this is the idea that sharks don't get cancer.
``That idea is wrong. Sharks do get cancer,'' said John C. Harshbarger of George Washington University.
Harshbarger, who heads the federally sponsored Registry of Tumors in Lower Animals, described 40 cases of tumors that have been found in sharks and their close cousins, the skates, rays and chimerids.
Harshbarger presented the data at a meeting in San Francisco of the American Association for Cancer Research. He said that most of the cases have long been known to scientists, although he added two new ones-kidney cancer in a dogfish shark and lymphoma blood cancer in a sandbar shark.
``This is good science that shows us that sharks can get cancer,'' commented biologist John Coffey of Johns Hopkins University. ``I don't think there is any benefit to buying shark cartilage and eating it, any more than I think that eating a rabbit will make me run faster.''
Shark cartilage proponents dismissed the latest work as nothing new.
``It's true that some sharks get cancer. I said this in my book,'' said William Lane, author of the 1992 book ``Sharks Don't Get Cancer.'' ``My publisher thought it would be bad to call it, `Almost No Sharks Get Cancer.'''
Still, Lane said, cancer is far less common in sharks that in other ocean creatures.
Harshbarger questions that assertion, too. He said that all of the shark cases reported so far are anecdotal discoveries made mostly by sharp-eyed biologists. No one has ever done a systematic survey of sharks to see how often they get cancer or whether they are less prone to the disease than other fish.
In theory, shark cartilage might stop cancer by blocking the growth of new blood vessels, a necessary step in tumor spread. However, biologist Gary K. Ostrander of Johns Hopkins said there is no animal or human research to support its anticancer properties.
A study published in November 1998 concluded that shark cartilage pills were ineffective in 47 patients with advanced breast, colon, lung, and prostate cancer.
A much larger study will begin later this year at the Mayo Clinic to test shark cartilage on 600 terminally ill patients with breast and colon cancer.
The study will be sponsored by the National Institutes of Health and Lane Labs, a company founded by Lane's son Andrew, that sells shark cartilage.
Harshbarger said that 23 of the 40 tumors in the registry are in sharks, while the rest are in their close relatives. The bodies of all these creatures contain cartilage but no bone.
Source: Associated Press
White Tea May Help Fight Cancer
White tea appears to have more potent anticancer qualities than green tea, according to studies performed at the Linus Pauling Institute of Oregon State University.
The researchers tested the tea to determine whether it could help prevent genetic mutations in bacteria, and colon and rectal cancer in cancer-prone rats.
The rats were offered white tea-at a strength equivalent to steeping a tea bag in a cup for five minutes-instead of water for eight weeks.
In both experiments, white tea was shown to have a strong protective effect, said Dr. Gilberto Santana-Rios. By some measures, white tea offered twice the protection of water alone, and significantly more protection than green tea, he said.
Although all teas are made from the same type of plant, they differ in which parts of the plant are collected and how they are processed.
The most common tea in North America and much of Europe, black tea, is also the most heavily processed. For black tea the leaves are withered, rolled, roasted and dried, and when steeped they produce a characteristic dark beverage.
For white tea, the leaves and white-colored buds of the plant are merely steamed and dried, leaving a mixture that looks like dried basil flecked with small white buds. When steeped in hot water, the result is a pale liquid with a taste reminiscent of green tea.
Source: Reuters Health
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